Tera-Hertz spectroscopy of Transition Metal Clusters
We apply Multiple Photon Dissociation (MPD) Spectroscopy in the far-infrared (more fashionably called Tera-Hertz region) to obtain the vibrational spectra of transition metal clusters in the gas phase. More precisely, weakly bound complexes of the cluster with rare gas atoms are irradiated and their depletion is used as probe for the absorption process. For anionic clusters we use the thermionic electron detachment after absorption of very many IR photons to obtain their IR spectra. Experimental far-IR spectra are typically recorded in the 85-500 cm-1 region to cover the range of the structure-specific vibrational fundamentals, i.e., the finger-print range, for the metal clusters.
Comparison with calculated vibrational spectra obtained, for instance, by using DFT
methods, allows for structural assignments.
Recently we have been able to investigate the infrared spectra of neutral gold clusters in the 47-220 cm-1 range. First results have been reported for Au7 , Au19 , and Au20 . For more details see here.
The structures of small cationic gas-phase platinum clusters (Communication) D. J. Harding, C. Kerpal, D. M. Rayner, A. Fielicke, J. Chem. Phys. 136 (2012) 211103.
Structure Determination of Anionic Metal Clusters via Infrared Resonance Enhanced Multiple Photon Electron Detachment Spectroscopy M. Haertelt, V. J. F. Lapoutre, J. M. Bakker, B. Redlich, D. J. Harding, A. Fielicke, and G. Meijer, J. Phys. Chem. Lett. 2 (2011) 1720.
The Structure of Rh8+ in the Gas Phase (Communication) D. J. Harding, T. R. Walsh, S. M. Hamilton, W. S. Hopkins, S. R. Mackenzie, P. Gruene, M. Haertelt, G. Meijer, and A. Fielicke, J. Chem. Phys. 132 (2010) 011101.
Isomer selective infrared spectroscopy of neutral metal clusters A. Fielicke, C. Ratsch, G. von Helden, and G. Meijer, J. Chem. Phys. 122 (2005) 091105 (4 pages).
Structure determination of isolated metal clusters via far-infrared spectroscopy A. Fielicke, A. Kirilyuk, C. Ratsch, J. Behler, M. Scheffler, G. von Helden, and G. Meijer, Phys. Rev. Lett. 93 (2004) 023401.
Structures of neutral (left) and cationic (right) niobium clusters Nbn0/+ (n=5-9)